Generally, a method of pressure regulated supercritical fluid fractionation of oil seed extraction materials which can be utilized to refine oil seed extraction material established in an amount of supercritical fluid. Specifically, a method of pressure regulated supercritical fluid fractionation of corn germ extraction material to produce a refined corn oil extraction material.
Oil Seed extraction materials which include materials extracted from the entirety or parts of various seeds such as corn (typically the corn germ), cotton, rape, safflower, sunflower, flax, or the like, can be generated by a wide variety of extraction methods, such as, solvent extraction, hydraulic pressing, expeller pressing, or the like. Useful solvents for solvent extraction can include hexane, n-hexane, isopropyl alcohol, supercritical fluids, supercritical carbon dioxide, and other similar solvents.
There is a large commercial market for oil seed extraction materials suitably refined to meet the varying standards for direct use as fuels, the production of fuels, the processing of foods, addition to foods, and food. The oil seed extraction materials obtained by these extraction methods exhibit a correspondingly wide range of compositions as mixtures of neutral extraction oils, fatty acids, and a greater or lesser amount of undesired impurities. For example, the undesired impurities in the corn germ extraction material can include one or more of: free fatty acids (FFA) from the degradation of corn germ oil by hydrolysis, phosphatides (hydratable and non-hydratable), organic compounds which contribute certain colors, flavors or odors, particulates entrained by the extracted corn germ extraction material, or the like.
A significant problem with the refining of oil seed extraction material including corn germ extraction material may be that while a wide variety of methods for the extraction of oil seed extraction material from oil seeds have developed over the past decades, relatively few methods of refining oil seed extraction material have developed over the same period. For example, corn germ extraction material continues to be refined by addition of a base such as sodium hydroxide, soda ash, sodium bicarbonate, potassium hydroxide, or the like, which reacts with FFA to produce an emulsion of neutral corn germ extraction oils, a soap mass (often referred to as the “soap stock”), and residual base. The emulsion can centrifuged to separate the neutral corn germ oils from the soap stock and the residual base. The neutral corn germ oils are typically combined with an amount of silica to trap residue soap stock, residual phosphorus, and trace metals. The silica being removed from the neutral corn germ extraction oils by filtration. The resulting neutral corn germ oils may be bleached to reduce color. The corn oil generated may be suitable for a wide variety of uses depending on the exact manner of applying the above-described general steps of the corn germ extraction material refining process.
While this centrifugal refining process is typically suitable for processing oil seed extraction materials and specifically suitable across the wide range of corn germ extraction material compositions generated by the various corn germ extraction material extraction techniques, it has certain disadvantages in that the centrifugal refining process involves the utilization of equipment costly to purchase and maintain, the various extraction processes and the centrifugal refining process may operate separate from one another without significant feed back from the refining process to the extraction process, and without limiting the disadvantages of the centrifugal refining process, may be more costly per unit of refined corn germ extraction material than necessary based upon the higher quality of corn germ extract materials being generated by more recently developed corn germ extraction material extraction processes.
Interestingly, due to the prevalence and overall suitability of conventional centrifugal refining process, developments in the refining of oil seed extraction materials and specifically corn germ extraction materials may not have addressed refining of oil seed extraction materials or corn germ extract materials in bulk by any alternate non-centrifugal extraction material refining process, but rather focus on the production of oil seed extraction material or corn germ extraction material fractions enriched in certain compounds. For example, U.S. Pat. No. 5,932,261 describes a process for production of a carotene rich refined oil fraction from a corn germ extraction material.
To address the unresolved problems associated with the utilization of conventional oil seed and corn germ extraction equipment and methods of refining oil seed extraction materials and specifically corn germ extraction materials, the instant invention provides devices and methods for the pressure regulated supercritical fluid fractionation of oil seed extraction materials and specifically of corn germ extraction materials.